Extrinsic Peak in the Susceptibility of Incipient Ferroelectric KTa<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>: Li

Höchli, U. T.; Weibel, H.; Boatner, L. A.

doi:10.1103/physrevlett.41.1410

Cited by 63 publications

(30 citation statements)

References 6 publications

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“…[12][13][14][15][16][17][18][19] Now the problem seems to be settled: When the Li concentration x exceeds 5 mol%, the para and ferroelectric phase boundary is well defined. In the region of 2<x<3, the phase boundary becomes obscured, and below the concentration, the dipole glass state is main feature of KTL.…”

Section: Introductionmentioning

confidence: 99%

Second-harmonic-generation microscopic observations of polar state in Li-dopedKTaO3under an electric field

2005

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Incipient ferroelectric KTaO 3 with off-center Li impurity of the critical concentration of 2.8 mol% was investigated in order to clarify the dipole state under electric field. Using optical second-harmonic generation (SHG) microscope, we observed a marked history dependence of SHG intensity through zero-field cooling (ZFC), zero-field heating (ZFH), field heating after ZFC (FH/ZFC) and FH after field cooling (FH/FC). These show different paths with respect to temperature: In the ZFC/ZFH process, weak SHG was observed at low temperature, while in the FH/ZFC process, relatively high SHG appears in a limited temperature range below T F depending on the field strength, and in the FC and FH/FC processes, the SHG exhibits ferroelectric-like temperature dependence: it appears at the freezing temperature of 50K, increases with decreasing temperature and has a tendency of saturation. These experimental results strongly suggest that dipole glass state or polar nano-clusters which gradually freezes with decreasing temperature is transformed into semi-macroscopic polar state under the electric field. However at sufficiently low temperature, the freezing is so strong that the electric field cannot enlarge the polar clusters. These experimental results show that the 2 polar nano-cluster model similar to relaxors would be more relevant in KTaO 3 doped with the critical concentration of Li. Further experiments on the anisotropy of SHG determine that the average symmetry of the field-induced polar phase is tetragonal 4mm or 4. The tetragonality is also confirmed by the X-ray diffraction measurement.

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Section: Introductionmentioning

confidence: 99%

Second-harmonic-generation microscopic observations of polar state in Li-dopedKTaO3under an electric field

2005

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“…In general, A-site substitution modulates the ferroelectric transition by affecting the ferroelastic strains, which couples with the lattice distortions of the perovskite lattices, and the nature of Ti-O hybridization. As had been indicated by extensive investigation into A-site chemical substitutions, such as Li + -doped KTaO 3 and Ca 2+ -doped SrTiO 3 , dielectric transitions from quantum paraelectric to quantum ferroelectric and then to relaxor were resulted by an increasing level of substitution [4][5][6][7]. These interesting phenomena have been addressed as the impurity-induced ferroelectricity or polarcluster effect, where the dipolar nano/micro-regions are induced by the off-centered impurities or their corresponding defect associations with high polarizability [8].…”

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confidence: 96%

Dielectric anomalies of Pb0.7La0.2TiO3-based perovskite

Soon

Wang

2006

J Electroceram

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Dielectric transitions from normal ferroelectric to relaxor-like and then to quantum paraelectric-like behaviour were observed by substituting 10 to 60% of Ca 2+ for Pb 2+ into A-site of Pb 0.7 La 0.2 TiO 3 with the required stoichiometry of Pb 0.7(1−x) Ca 0.7x La 0.2 TiO 3 (PCLT). The quantum ferroelectric relation that commonly applies to SrTiO 3 -based perovskites, T max α(X − X c ) 1/2 , fails to describe the observed dielectric anomalies in PCLT, whereby the transition temperature vanishes with a finite slope. Quantum ferroelectric behaviour that exhibits a sharp dielectric peak but violates the Curie-Weiss law was not observed throughout the composition range studied. Unlike the typical quantum paraelectric SrTiO 3 , the quantum paraelectric-like behaviour observed for PCLT with x = 0.55 and 0.60 exhibit negative transition temperatures, as shown by the fittings to both the CurieWeiss and Barrett's relations. Thermal hysteresis was surprisingly observed in substituted PCLT with x = 0.30 and 0.40 that exhibit frequency dispersive relaxation. To establish a correlation between the dielectric anomalies and structural parameters, analyses on global and local perovskite lattices were carried out using X-ray diffraction technique and microRaman spectroscopy.

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“…For x > x c , long range tetragonal order develops, which manifests itself as a sharp drop in dielectric permittivity, the more pronounced the lower the frequency 4,5 . Yet, no macroscopic switchable polar order is observed if cooled in zero field 6,7 . For x > x c , KLT is therefore structurally ordered but not ferroelectric at low temperature 7 .…”

Section: Introductionmentioning

confidence: 99%

“…Yet, no macroscopic switchable polar order is observed if cooled in zero field 6,7 . For x > x c , KLT is therefore structurally ordered but not ferroelectric at low temperature 7 . The present study has focused more narrowly on the nature of this critical concentration and on the changes in collective dynamics taking place on either side of it.…”

Section: Introductionmentioning

confidence: 99%